Development began in 1956 as the Vertol model 114. In Jun 1959 a US Army contract for 5 prototype effective battlefield medium/heavy lift helico ... The CH-47 Chinook is tandem rotor medium/heavy lift helicopter with a pair of 3 bladed, contra-rotating rotors atop a square section, semi-monoco ... Hugely successful design has been developed and improved for over forty years in a number of versions and for a variety of customers, with every ... Also built by Kawasaki in Japan and Meridionali in Italy. Chinooks have served in all branches of the US military and para-military and the armed ... The much improved variants CH-47D and CH-47F are listed separately